Korean Full Age Calculator
Age from date of birth to reference date, next birthday, and elapsed days. Multiple birthdays and leap years for February 29 are calculated together.
Required except for selection. Input is calculated in this tab and disappears on refresh.
Result
Click ‘Calculate All’ after input.
Share result
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Calculation method and criteria
This tool calculates age and the next birthday based on whether the birthday has occurred and the rule you choose for leap-day birthdays.
Actual example
Someone born on 2000-10-04 is 25 years old as of 2026-10-03, with 1 day until their birthday. Someone born on 2000-10-03 is 26 years old on that date; their birthday is today.
Frequently Asked Questions
How is the age calculated?
Calculate age as the reference year minus the birth year, subtracting 1 if the birthday has not yet occurred that year. The birthday itself marks the age increase.
When is February 29 birthday counted in a common year?
You can choose 1st day of March or 28th February. The default is 1st day of March, but it is only a calculation assumption, not a function to set legal or institutional standards.
How are the next birthday and elapsed days counted?
If the standard date is a birthday, it is displayed as today with 0 days remaining. From birth date, the birth date is set to 0 days; time, time zone, and qualification are not reflected.
Calculation criteria and reference materials
The calculation formula and scope of this tool are disclosed in the above description. Examples can be checked by substituting input values into the formula or following the specified string and calendar handling rules.
Verification of calculation criteria: · Calculation·verification principles · Report errors